Compositions and Methods for the Treatment of Heart Failure

ABSTRACT

The invention provides a therapeutic composition comprising an aqueous buffer, and a therapeutic agent that proves the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure and simultaneously increasing left ventricular ejection without affecting the blood pressure or heart rate.

CROSS REFERENCE

This application claims priority to U.S. Application No. 60/922,047, filed on Apr. 5, 2007, the content of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This invention relates generally to compositions and methods for treating heart failure. More specifically, the invention relates to a pharmaceutical composition for the treatment of heart failure that can be administered intermittently and has a continuous therapeutic effect.

BACKGROUND OF THE INVENTION

Heart failure (HF) is a pathological condition in which the heart is unable to pump blood at a rate required for normal metabolism and physical activity. Frequently, the exact causes of HF (particularly chronic HF) are unknown, but may be one or more of hypertension, myocardial injury, ischemic heart disease, cardiac valve abnormalities, coronary artery diseases, and abnormal electrical conduction within the heart. Alone or in combination, these conditions cause an increased chronic load on the heart'which triggers three major compensatory mechanisms: the adrenergic system, the renin-angiotensin-aldosterone system, and ventricular hypertrophy. Although these mechanisms allow the heart to adapt and maintain adequate cardiac output, over time, they also bring about deleterious effects on the heart and cardiovascular system. These deleterious effects include cardiac myocyte hypertrophy leading to wall thickening and reduced contractility; elevated cytosolic calcium, causing impaired myocardial relaxation, vasoconstriction and aldosterone-induced salt and water retention, both of which may cause hypertension and additional load on the heart.

In current medical practice, patients are treated with one or more drugs that reduce stress on the heart. These drugs include vasodilators, diuretics, angiotensin receptor blockers, and beta-blockers. In combination with a healthy life style, these drug regimens improve symptoms and quality of life for the patient. Nevertheless, the pathophysiological changes in the heart progress over time causing debilitation of the heart and decreasing mobility and declining quality of life for the patient.

Poloxamer 188 (“P-188” or “P188”) has been shown to improve cardiac output and reverse the heart failure associated with muscular dystrophy. Cardiac muscle cells exhibited a contractile defect that resulted from sustained high levels of cytosolic calcium. P-188, when added to an in vitro cardiac muscle preparation, appeared to seal tears in the muscle cell membrane, and thereby prevent an influx of calcium and allow cells to normalize their calcium levels. All of these affects of P-188 on cardiac muscle cells were observed in vitro, by placing the cell in a solution containing a fairly high concentration of P-188. Following exposure to P-188 treatment, heart muscle exhibited an improved ability to relax (improved diastolic function) and increased cardiac output. Furthermore, it is unknown whether these results are applicable to heart failure other than that associated with muscular dystrophy.

It would be desirable, to provide a treatment for heart failure that would slow or reverse the pathophysiological changes of the cardiac muscle tissue and could be administered intermittently but have a continuous therapeutic effect. Such a treatment would overcome many of the limitations and disadvantages inherent in the presently available treatments described above.

SUMMARY OF THE INVENTION

In one aspect, the present invention relates to a therapeutic composition which includes an aqueous buffer, and a therapeutic agent that improves the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure or increasing left ventricular ejection without substantially affecting the blood pressure or heart rate.

As used herein, the term “significantly affecting the blood pressure or heart rate” refers to statistically significant deviation from the blood pressure or heart rate before the composition of this invention is administered. In general, a change that is not statistically significant is small enough that it can be ignored.

In some embodiments, the therapeutic agent improves the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure without substantially affecting the blood pressure or heart rate.

In some embodiments, the therapeutic agent improves the functioning of a diseased heart by increasing left ventricular ejection without substantially affecting the blood pressure or heart rate.

In some embodiments, the therapeutic agent that improves the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure and simultaneously increasing left ventricular ejection without substantially affecting the blood pressure or heart rate.

In some embodiments, the therapeutic composition improves the functioning of the diseased heart continuously for at least 24 hours (e.g., at least 48 hours, at least 7 days, or at least one month) following each administration of the therapeutic composition.

In some embodiments, the therapeutic agent contained in the therapeutic composition improves the functioning of a diseased heart independently of its concentration in the blood for at least 24 hours (e.g., at least 48 hours, at least 7 days, or at least one month) following each single administration of the therapeutic composition.

In some embodiments, the therapeutic agent is a polyoxyalkylene block copolymer. In some other embodiments, the therapeutic agent has a molecular weight in the range of 3,000 to 18,000. In some embodiments, the therapeutic agent is a poloxamer or poloxamine (e.g., Poloxamer 188, Poloxamer 407, Poloxamer 338, or Poloxamine 1107).

In some embodiments, the therapeutic composition is injectable or infusible.

In some embodiments, the disease of the heart is heart failure, e.g., chronic heart failure (such as ischemic heart failure) or acute heart failure.

Another aspect of this invention relates to a method for treating or ameliorating heart failure in a patient. The method includes administering to the patient a therapeutic composition comprising an aqueous buffer, and a therapeutic agent that improves the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure or increasing left ventricular ejection without affecting the blood pressure or heart rate.

In some embodiments, the therapeutic composition used for treating or ameliorating heart failure improves the functioning of the diseased heart continuously for at least 24 hours (e.g., at least 48 hours, at least 7 days, or at least one month) following each administration of the therapeutic composition.

In some embodiments, the therapeutic agent contained in the therapeutic composition for preventing heart failure improves the functioning of a diseased heart independently of its concentration in the blood for at least 24 hours (e.g., at least 48 hours, at least 7 days, or at least one month) following each single administration of the therapeutic composition.

In some embodiments, the therapeutic agent contained in the therapeutic composition is a polyoxyalkylene block copolymer. In some other embodiments, the therapeutic agent has a molecular weight in the range of 3,000 to 18,000. In some embodiments, the therapeutic agent is a poloxamer or poloxamine (e.g., Poloxamer 188, Poloxamer 407, Poloxamer 338, or Poloxamine 1107).

The therapeutic compositions of this invention can be used together with therapeutic compositions useful for treating cardio or heart diseases, e.g., hypertension or congestive heart failure. Accordingly, the therapeutic compositions of this invention can also include compounds useful for treating such cardio or heart diseases.

As such, in some embodiments, a composition of this invention can further include an agent selected from the group consisting of angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), beta-blockers, diuretics, digoxin, and anti-arrhythmic drugs. Examples of ACE inhibitors suitable for the compositions of this invention include, but are not limited to, captopril, benazepril, enalapril, lisinopril, fosinopril, ramipril, perindopril, quinapril, moexipril, and trandolapril. Examples of ARBs suitable for this invention include losartan, candesartan, irbesartan, and valsartan. Examples of beta-blockers suitable for the compositions of this invention include, but are not limited to, alprenolol, carteolol, levobunolol, mepindolol, metipranolol, nadolol, oxprenolol, penbutolol, pindolol, propranolol, sotalol, timolol, acebutolol, atenolol, betaxolol, bisoprolol, esmolol, metoprolol, nebivolol, carvedilol, celiprolol, labetalol, and butaxamine. Examples of diuretics suitable for this invention include, but are not limited to, calcium chloride, ammonium chloride, amphotericin B, lithium citrate, Goldenrod, Juniper, dopamine, acetazolamide, dorzolamide, bumetanide, ethacrynic acid, furosemide, torsemide, glucose, mannitol, amiloride, spironolactone, triamterene, bendroflumethiazide, hydrochlorothiazide, caffeine, and theophylline. Examples of anti-arrhythmic drugs suitable for this invention include, but are not limited to, disopyramide, procainamide, quinidine, lidocaine, phenyloin, flecamide, propafenone, propranolol, timolol, metoprolol, sotalol, atenolol, amiodarone, sotalol, bretylium, verapamil, and diltiazem.

In some embodiments, the therapeutic composition is injectable or infusible for treating or ameliorating heart failure.

In some embodiments, the disease of the heart to be treated or ameliorated is heart failure, e.g., chronic heart failure (such as ischemic heart failure) or acute heart failure.

Also within the scope of this invention are methods for treating, ameliorating, or preventing heart failure in a subject. The method includes administering to the patient a therapeutic composition comprising an aqueous buffer, and a therapeutic agent that improves the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure or increasing left ventricular ejection, without substantially affecting the blood pressure or heart rate.

In some embodiments, the methods of this invention improve the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure without substantially affecting the blood pressure or heart rate.

In some embodiments, the methods of this invention improve the functioning of a diseased heart by increasing left ventricular ejection without substantially affecting the blood pressure or heart rate.

In some embodiments, the methods of this invention improve the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure and simultaneously increasing left ventricular ejection without substantially affecting the blood pressure or heart rate.

In some embodiments, the methods of this invention improve the functioning of the heart continuously for at least 24 hours (e.g., at least 48 hours, at least 7 days, or at least one month) following each administration of the therapeutic composition.

In some embodiments, the therapeutic agent contained in the compositions of this invention or used for the methods of this invention improves the functioning of a diseased heart independently of its concentration in the blood for at least 24 hours (e.g., at least 48 hours, at least 7 days, or at least one month) following each single administration of the therapeutic composition.

In some embodiments, the therapeutic agent used for the methods of this invention is a polyoxyalkylene block copolymer. In some other embodiments, the therapeutic agent has a molecular weight in the range of 3,000 to 18,000. In some other embodiments, the therapeutic agent is a poloxamer or poloxamine (e.g., Poloxamer 188, Poloxamer 407, Poloxamer 338, or Poloxamine 1107).

In some embodiments, the therapeutic agent used for the methods of this invention is injectable or infusible for treating, ameliorating, or preventing heart failure.

In some embodiments, the disease of the heart to be treated, ameliorated, or prevented by the methods of this invention is heart failure, e.g., chronic heart failure (such as ischemic heart failure) or acute heart failure.

The methods of this invention can be used together with other methods useful for treating cardio or heart diseases, e.g., hypertension or congestive heart failure. Accordingly, the methods of this invention can also include administering compounds useful for treating such cardio or heart diseases.

As such, in some embodiments, the methods of this inventions include administering the therapeutic agent to the patient in the amount of 0.15 mg/kg to about 480 mg/kg, e.g., about 460 mg/kg, about 250 mg/kg, about 150 mg/kg, about 15.3 mg/kg, about'4.6 mg/kg, about 1.5 mg/kg, or about 0.46 mg/kg.

In some further embodiments, the methods of this invention further include administering an agent selected from the group consisting of angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), beta-blockers, diuretics, digoxin, and anti-arrhythmic drugs. Examples of ACE inhibitors suitable for the compositions of this invention include, but are not limited to, captopril, benazepril, enalapril, lisinopril, fosinopril, ramipril, perindopril, quinapril, moexipril, and trandolapril. Examples of ARBs suitable for this invention include, but are not limited to, losartan, candesartan, irbesartan, and valsartan. Examples of beta-blockers suitable for the compositions of this invention include, but are not limited to, alprenolol, carteolol, levobunolol, mepindolol, metipranolol, nadolol, oxprenolol, penbutolol, pindolol, propranolol, sotalol, timolol, acebutolol, atenolol, betaxolol, bisoprolol, esmolol, metoprolol, nebivolol, carvedilol, celiprolol, labetalol, and butaxamine. Examples of diuretics suitable for this invention include, but are not limited to, calcium chloride, ammonium chloride, amphotericin B, lithium citrate, Goldenrod, Juniper, dopamine, acetazolamide, dorzolamide, bumetanide, ethacrynic acid, furosemide, torsemide, glucose, mannitol, amiloride, spironolactone, triamterene, bendroflumethiazide, hydrochlorothiazide, caffeine, and theophylline. Examples of anti-arrhythmic drugs suitable for this invention include, but are not limited to, disopyramide, procainamide, quinidine, lidocaine, phenyloin, flecamide, propafenone, propranolol, timolol, metoprolol, sotalol, atenolol, amiodarone, sotalol, bretylium, verapamil, and diltiazem.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the effect of P-188 on left ventricular ejection fraction in severe heart failure animals.

FIG. 2 shows the effect of P-188 on left ventricular fractional shortening in severe heart failure animals.

FIG. 3 shows the effect of P-188 on left ventricular end-diastolic diameter in heart failure animals at different dosages.

FIG. 4 shows the effect of P-188 on left ventricular end-diastolic pressure in heart failure animals at different dosages.

FIG. 5 shows the effect of P-188 on left ventricular end-systolic diameter in heart failure animals at different dosages.

FIG. 6 shows the effect of P-188 on left ventricular ejection fraction in heart failure animals at different dosages.

DETAILED DESCRIPTION OF THE INVENTION

Compositions of this Invention

In one aspect, the present invention provides therapeutic compositions each of which includes an aqueous buffer, and a therapeutic agent that improves the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure and simultaneously increasing left ventricular ejection without affecting the blood pressure or heart rate. These compositions have a physiologically acceptable pH, e.g., in the range of 4.5 to 7.5.

Suitable therapeutic agents include polyoxyalkylene block copolymer (e.g., those with a molecular weight in the range of 3,000 to 18,000). Examples of the polyoxyalkylene block copolymers include Poloxamers and Poloxamines.

Poloxamers are a series of polyoxyalkylene block copolymers having the general structure:

HO(C₂H₄O)_(a)(C₃H₆O)_(b)(C₂H₄O)_(a)H

in which b is at least 15. The average molecular weights of the poloxamers range from about 1,000 to greater than 16,000 daltons. For example, Poloxamer 188 comprises a polyoxypropylene center block (with about 30 repeating units) flanked on either end by polyoxyethylene segments (each having about 75 repeating units) and has an average molecular weight of approximately 8,300. Poloxamer 407 comprises a polyoxypropylene center block (with about 67 repeating units) flanked on either end by polyoxyethylene segments (each having about 98 repeating units) and has an average molecular weight of approximately 11,500. Poloxamer 338 comprises a polyoxypropylene center block (with about 54 repeating units) flanked on either end by polyoxyethylene segments (each having about 128 repeating units) and has an average molecular weight of approximately 14,000.

Poloxamers can be prepared by methods known in the art for synthesizing block copolymers. For instance, the preparation of a poloxamer comprises synthesizing the center block and then capping the ends of the enter block with two polymer blocks. Specifically, the hydrophobic center block can be synthesized, e.g., in a base catalyzed ether condensation reaction using propylene glycol as the initiator and sequentially adding propylene oxide under an inert, anhydrous atmosphere, at elevated temperature and pressure. Upon reaching the desired molecular weight of the center block, the propylene oxide reactant is replaced by ethylene oxide. The polymer is then extended by the addition of ethylene oxide to form a hydrophilic segment of polyoxyethylene at each end of the polyoxypropylene block. Finally, the reaction is terminated by neutralization of the catalyst with an acid. More than thirty different poloxamers have been synthesized which range in molecular weight from 1,000 to 15,000. The polyoxyethylene content of the molecule may vary from 10% to 90% of the weight of the molecule. See, e.g., Reeve, L. E., “The Poloxamers: Their Chemistry and Medical Applications,” pp. 231-249 in Handbook of Biodegradable Polymers, Eds. Domb, Kost and Wiseman, Harwood Academic Publishers (1997). Understandably, one can control the number of repeating propylene oxide or ethylene oxide units, and thus the length and weight of each of the poly(ethyleneoxide) and poly(propyleneoxide) blocks by changing the polymerization condition and time, or even the method. Specific examples of synthesis and characterization of poloxamers can be found in public literature and patent database. See, e.g., U.S. Pat. Nos. 6,977,045, 6,761,824, 5,811,080, 5,990,241, 6,359,014, 6,448,371, 6,747,064, 6,933,286, 5,567,859, RE 37,285, RE 36,665, RE 38,558, etc.

Poloxamines are four-branched block polyoxyalkylene block copolymers of poly(ethyleneoxide) and poly(propyleneoxide) having the general structure:

Poloxamine 1107, for example, has an average molecular weight of 15,400, and non-ionic surfactant properties. It has been used as a cellular membrane sealant, e.g., for repairing radiopermeabilized erythrocyte membranes.

Poloxamers and poloxamines are freely soluble in water, and are soluble in polar solvents. The Poloxamers are liquids, pastes or solids, depending largely on their polyoxyethylene to polyoxypropylene ratio and, secondarily, on their total molecular weight. In general, poloxamers having an average molecular weight of 3,000 or less are liquids if their polyoxyethylene content is not more than 50%. Poloxamers with molecular weights between 3,000 and 5,000 are liquids only if their polyoxyethylene content is 20% or less. Pastes range in molecular weight from 3,300 to 6,600 with a polyoxyethylene content between 30% and 50%. Solid poloxamers are the largest, having molecular weights of 5,000 to 15,000 and polyoxyethylene content of 70% or greater.

As such, the Poloxamers and poloxamines (e.g., Poloxamer 188, Poloxamer 338, Poloxamer 407, or Poloxamine 1107) can be dissolved into water or an aqueous buffer to the desired concentration, e.g., 5-300 g/L, to give a polymer solution that can be later used to prepare a composition of this invention or practice the methods of this invention.

The compositions of this invention also include an aqueous buffer. As used herein, the term “aqueous buffer” refers to a water solution which resists change in hydronium ion and the hydroxide ion concentration (and consequent pH) upon addition of small amounts of acid or base, or upon dilution. Buffer solutions consist of a weak acid and its conjugate base (more common) or a weak base and its conjugate acid (less common). The buffer can be prepared by methods well known in the art with the appropriate buffering agents to give the desired pH value. Examples of the suitable buffering agents include hydrochloric acid, lactic acid, acetic acid, citric acid, malic acid, maleic acid, pyruvic acid, succinic acid, tris-hydroxymethylaminomethane, sodium hydroxide, sodium bicarbonate, phosphoric acid, sodium phosphate, and other biologically acceptable buffering agents. Of course, aqueous buffers are readily available commercially and they can be used in preparation of the compositions of this invention without further treatment.

Uses of the Compositions of this Invention

As used herein, the term “heart failure” refers to a condition that can result from any structural or functional cardiac disorder that impairs the ability of the heart to fill with or pump a sufficient amount of blood throughout the body. As used herein, the term “chronic heart failure” refers to a sustained inability of the heart to pump blood forward at a sufficient rate to meet metabolic demands. Examples of chronic heart failure include systolic dysfunction, diastolic dysfunction, right-sided heart failure, and ischemic heart failure. As used herein, the term “acute heart failure” refers to acute decompensation episodes in chronic heart failure patients.

The compositions of this invention can be used for treating or ameliorating a diseased heart in a patient or to prevent certain heart disease in a subject (e.g., a human patient or animal). The disease can be heart failure, e.g., chronic heart failure (such as ischemic heart failure) or acute heart failure.

For instance, a composition of this invention can be injected or infused into the blood vessel of a patient (or a subject) with a diseased heart and in need of the treatment. The therapeutic agent in the composition (e.g., a poloxamer or poloxamine) then circulates into the heart. Not wishing to be bound by this theory, the therapeutic agent contained in the compositions of this invention may decrease the contractile stress of the heart muscle, and in a condition of low membrane dystrophin levels, may even decrease membrane damage enough to allow the heart to repair itself. In other words, the therapeutic composition may aid in the repair of membrane damage in a diseased heart without the need of a surgical procedure to unload the heart.

The efficacy of the compositions of this invention in treating, ameliorating, or even preventing heart disease can be determined by methods known in the art, e.g., by measuring the blood flow rate or volume in vitro or in an animal model or the pharmacokinetics of the therapeutic agent in the composition. See, e.g., Grindel J. M. et al., Biopharm. Drugs Dispos., 2002, 23: 87-103.

One specific example to ways to determine the efficacy of the compositions or methods of this invention is to measure the ejection fraction, specifically the left ventricular ejection fraction (LVEF). Ejection fraction refers to the fraction of blood pumped out of a ventricle with each heart beat. By definition, the volume of blood within a ventricle immediately before a contraction is known as the end-diastolic volume. Similarly, the volume of blood left in a ventricle at the end of contraction is end-systolic volume. The difference between end-diastolic and end-systolic volumes is the stroke volume, the volume of blood ejected with each beat. Ejection fraction is the fraction of the end-diastolic volume that is ejected with each beat; that is, it is stroke volume (SV) divided by end-diastolic volume (EDV).

Ejection fraction is commonly measured by echocardiography, in which the volumes of the heart's chambers are measured during the cardiac cycle. Ejection fraction can then be obtained by dividing stroke volume by end-diastolic volume as described above.

Other methods of measuring ejection fraction include cardiac MRI, fast scan cardiac computed axial tomography (CT) imaging, and ventriculography. The historical gold standard for the measurement of ejection fraction is ventriculography.

The shortening fraction (or “fractional shortening”) is a slightly different way of measuring left ventricle performance. Instead of measuring and ratio-ing blood volumes, the shortening fraction measures and ratios the change in the diameter of the left ventricle between the contracted and relaxed states:

$\frac{{{LV}\mspace{14mu} {end}\text{-}{diastolic}\mspace{14mu} {diameter}} - {{LV}\mspace{14mu} {end}\text{-}{systolic}\mspace{14mu} {diameter}}}{{LV}\mspace{14mu} {end}\text{-}{diastolic}\mspace{14mu} {diameter}}.$

Other methods for determining the efficacy of the compositions or methods of this invention include the left ventricular end-diastolic diameter (or dimension) or the left ventricular end-systolic diameter (or dimension), which measures the actual ventricle's diameter (or dimension) and correlates to the performance of the left ventricle. Additionally, the efficacy can be determined by measuring the left ventricular end-diastolic pressure (LVEDP) or left ventricular end-diastolic volume (LVEDV), e.g., with a pressure or pressure/volume catheter inserted directly into the left ventricle.

Set forth below are some examples that illustrate use of the compositions of this invention. These examples are intended only to be illustrative of, not in any way limiting, this invention.

All publications cited herein are incorporated by reference in their entireties.

Example 1 Effect on Heart Failure

In a rat myocardial infarction (MI) heart failure model, the left anterior descending coronary artery (LAD) is tied off to produce an infarction of greater than 40%. The rats become stable after 1 to 3 weeks and in 3 weeks exhibit significant left ventricular (LV) dysfunction. 8-weeks post-MI rats are used due to their loss of dystrophin. Control groups include untreated heart failure rats, sham-operated animals where the LAD was exposed but not tied off as well as rats that did not undergo the surgery (normal).

On the day of treatment, rats were infused with P-188 at 460 mg/kg over a 30 minute period and the heart was catheterized and hemodynamics was monitored over a 4-hr period.

Compared with untreated MI rats, P-188 treatment caused a significant decrease in left ventricular end-diastolic pressure (LVEDP), as shown in FIG. 4. As shown in FIG. 1, at the dosage of 460 mg/kg, administration of P-188 also caused a significant increase in left ventricular ejection fraction (LVEF), a measurement that indicates the ability of the heart to empty its content during systole. Additionally, as shown in FIG. 2, it also caused a significant increase in left ventricular fractional shortening in severe heart failure rats. The heart rate (HR), left ventricular systolic pressure (LVSP), left ventricular isovolumic contraction (LV+dP/dt), and left ventricular end-systolic volume did not change significantly.

The results indicate that P-188 had an effect on cardiac hemodynamics. The approximate 25% increase in ejection fraction was clinically significant. Ejection fraction is the percent of end-diastolic volume that is ejected as the stroke volume and is a measurement of pump function. It can be influenced by blood pressure (afterload), the amount of blood returning to the heart (preload), volume of the heart chamber, and heart rate. Additionally, P-188 treatment did not affect heart rate (HR), and did not increase afterload because LVSP did not rise. Thus, it appears that P-188 had an effect on preload, which can be influenced by venous return of blood to the heart as well as the ability of the heart to relax. LVEDP, also influenced by these parameters, was decreased. Since a significant drop in venous return should be accompanied by a change in blood pressure, which was not seen with P-188, it is likely that the results indicate that P-188 increased the relaxation properties of the working heart.

Example 2 Duration of Action

HF rats were infused with a single dose of P-188 and monitored by echocardiography at 2, 24, and 48 hour post infusion. Blood samples were also taken to determine serum concentrations of the P-188.

As was indicated in Example 1 and shown in FIG. 1, treatment of rats with severe HF with P-188 at 460 mg/kg resulted in a significant increase in left ventricular ejection fraction at 2 hours and was maintained out to 48 hours of treatment. As shown in FIG. 2, left ventricular fractional shortening, the change in diameter of the LV chamber from end-diastole to end-systole divided by the LVED diameter, was increased significantly after P-188 at all time points, particularly with an increase of 50% at 2 and 24 hours and a nearly 100% increase at 48 hours. Left ventricular dimension in both diastole and systole were unchanged during the first 24 hours. These results indicate an increase in contractility in the P-188 treated hearts that was sustained or improved over the 48 hours of the study.

The results obtained in this study are consistent with P-188 having an affect on the relaxation properties of the left ventricle. An increase in LV compliance with a concomitant increase in preload, resulting in a stretching of the myofibrils would be expected to increase fractional shortening, contractility, and ejection fraction at 460 mg/kg. This is consistent with the decrease in LV end-diastolic pressure seen in Example 1. The half-life for plasma clearance in the rat has been reported to range from 4.9 to 8.0 hours.

Example 3 Treatment at Different Doses

Rats with moderate or severe heart failure were treated with the compositions of this invention at 0.46 mg/kg, 1.5 mg/kg, 4.6 mg/kg, 15.3 mg/kg, and 460 mg/kg (amount of P-188/body weight of rats) over a 30-minute period. Also used in the same studies were a control group (CHF) and a Sham group. Neither of these groups received treatment but both represented an upper limit (CHF) and a lower limit (Sham) of the parameters being measured.

As shown in FIG. 3, treatment of P-188 at the dosages of 0.46-15.3 caused a significant decrease in the left ventricular end-diastolic pressure in moderate or severe heart failure rats. As shown in FIG. 4, all doses of P-188 lowered LVEDP compared with the untreated CHF rats. However, only the dosage of 1.5 mg/kg of P-188 caused an even more significant decrease in the left ventricular diastolic pressure, while the effects of other dosages were not as pronounced.

By contrast, as shown in FIG. 5 and FIG. 6, the P-188 dosage of 460 mg/kg caused a significant decrease in the left ventricular systolic diameter of the treated rats and a significant increase in the left ventricular ejection fraction, while the other dosages did not have as much effect.

OTHER EMBODIMENTS

It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims. 

1. A therapeutic composition comprising: an aqueous buffer, and a therapeutic agent that improves the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure or increasing left ventricular ejection without significantly affecting the blood pressure or heart rate.
 2. (canceled)
 3. The therapeutic composition of claim 1, wherein the therapeutic composition improves the functioning of the diseased heart continuously for at least 24 hours following each administration of the therapeutic composition. 4-6. (canceled)
 7. The therapeutic composition of claim 1, wherein the therapeutic agent improves the functioning of a diseased heart independently of its concentration in the blood for at least 24 hours following each single administration of the therapeutic composition.
 8. (canceled)
 9. The therapeutic composition of claim 1, wherein the therapeutic agent is a polyoxyalkylene block copolymer.
 10. The therapeutic composition of claim 9, wherein the therapeutic agent has a molecular weight in the range of 3,000 to 18,000.
 11. The therapeutic composition of claim 10, wherein the therapeutic agent is a poloxamer or poloxamine.
 12. The therapeutic composition of claim 11, wherein the therapeutic agent is one or more compounds selected from the group consisting of Poloxamer 188, Poloxamer 407, Poloxamer 338, and Poloxamine
 1107. 13. The therapeutic composition of claim 12, wherein the therapeutic agent is Poloxamer
 188. 14-16. (canceled)
 17. The therapeutic composition of claim 1, wherein the therapeutic composition is injectable or infusible.
 18. The therapeutic composition of claim 1, wherein the disease of the heart is heart failure.
 19. The therapeutic composition of claim 18, wherein the disease of the heart is chronic heart failure or acute heart failure.
 20. (canceled)
 21. The therapeutic composition of claim 18, wherein the disease of the heart is ischemic heart failure.
 22. The therapeutic composition of claim 1, further comprising an agent selected from the group consisting of angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs); beta-blockers, diuretics, digoxin, and anti-arrhythmic drugs.
 23. The therapeutic composition of claim 22, wherein the ACE inhibitors consist of captopril, benazepril, enalapril, lisinopril, fosinopril, ramipril, perindopril, quinapril, moexipril, and trandolapril; ARBs consist of losartan, candesartan, irbesartan, and valsartan; beta-blockers consist of alprenolol, carteolol, levobunolol, mepindolol, metipranolol, nadolol, oxprenolol, penbutolol, pindolol, propranolol, sotalol, timolol, acebutolol, atenolol, betaxolol, bisoprolol, esmolol, metoprolol, nebivolol, carvedilol, celiprolol, labetalol, and butaxamine; diuretics consist of calcium chloride, ammonium chloride, amphotericin B, lithium citrate, Goldenrod, Juniper, dopamine, acetazolamide, dorzolamide, bumetanide, ethacrynic acid, furosemide, torsemide, glucose, mannitol, amiloride, spironolactone, triamterene, bendroflumethiazide, hydrochlorothiazide, caffeine, and theophylline; anti-arrhythmic drugs consist of disopyramide, procainamide, quinidine, lidocaine, phenyloin, flecamide, propafenone, propranolol, timolol, metoprolol, sotalol, atenolol, amiodarone, sotalol, bretylium, verapamil, and diltiazem.
 24. A method of treating, ameliorating, or preventing heart failure in a subject, comprising administering to the subject in need thereof a therapeutic composition comprising an aqueous buffer, and a therapeutic agent that improves the functioning of a diseased heart by decreasing left ventricular end-diastolic pressure or increasing left ventricular ejection without substantially affecting the blood pressure or heart rate.
 25. (canceled)
 26. The method of claim 24, wherein the therapeutic composition improves the functioning of the diseased heart continuously for at least 24 hours following each administration of the therapeutic composition. 27-29. (canceled)
 30. The method of claim 24, wherein the therapeutic agent improves the functioning of a diseased heart independently of its concentration in the blood for at least 24 hours following each single administration of the therapeutic composition.
 31. (canceled)
 32. The method of claim 24, wherein the therapeutic agent is a polyoxyalkylene block copolymer.
 33. The method of claim 32, wherein the therapeutic agent has a molecular weight in the range of 3,000 to 18,000.
 34. The method of claim 33, wherein the therapeutic agent is a poloxamer or poloxamine.
 35. The method of claim 34, wherein the therapeutic agent is one or more compounds selected from the group consisting of Poloxamer 188, Poloxamer 407, Poloxamer 338, and Poloxamine
 1107. 36. The method of claim 35, wherein the therapeutic agent is Poloxamer
 188. 37-39. (canceled)
 40. The method of claim 24, wherein the heart failure is acute heart failure.
 41. The method of claim 24, wherein the heart failure is chronic heart failure.
 42. The method of claim 41, wherein the heart failure is ischemic heart failure.
 43. The method of claim 24, wherein the therapeutic composition is administered by injection or infusion.
 44. The method of claim 24, wherein the therapeutic agent in the composition is administered to the patient in the amount of 0.15 mg/kg to about 480 mg/kg.
 45. The method of claim 44, wherein the therapeutic agent in the composition is administered to the patient in the amount of about 460 mg/kg.
 46. The method of claim 44, wherein the therapeutic agent in the composition is administered to the patient in the amount of about 250 mg/kg.
 47. The method of claim 44, wherein the therapeutic agent in the composition is administered to the patient in the amount of about 15.3 mg/kg.
 48. The method of claim 44, wherein the therapeutic agent in the composition is administered to the patient in the amount of about 4.6 mg/kg.
 49. The method of claim 44, wherein the therapeutic agent in the composition is administered to the patient in the amount of about 1.5 mg/kg.
 50. The method of claim 44, wherein the therapeutic agent in the composition is administered to the patient in the amount of about 0.46 mg/kg.
 51. The method of claim 24, further comprising administering to the subject an agent selected from a group consisting of angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), beta-blockers, diuretics, digoxin, and anti-arrhythmic drugs.
 52. The method of claim 51, wherein the ACE inhibitors consist of captopril, benazepril, enalapril, lisinopril, fosinopril, ramipril, perindopril, quinapril, moexipril, and trandolapril; ARBs consist of losartan, candesartan, irbesartan, and valsartan; beta-blockers consist of alprenolol, carteolol, levobunolol, mepindolol, metipranolol, nadolol, oxprenolol, penbutolol, pindolol, propranolol, sotalol, timolol, acebutolol, atenolol, betaxolol, bisoprolol, esmolol, metoprolol, nebivolol, carvedilol, celiprolol, labetalol, and butaxamine; diuretics consist of calcium chloride, ammonium chloride, amphotericin B, lithium citrate, Goldenrod, Juniper, dopamine, acetazolamide, dorzolamide, bumetanide, ethacrynic acid, furosemide, torsemide, glucose, mannitol, amiloride, spironolactone, triamterene, bendroflumethiazide, hydrochlorothiazide, caffeine, and theophylline; anti-arrhythmic drugs consist of disopyramide, procainamide, quinidine, lidocaine, phenyloin, flecamide, propafenone, propranolol, timolol, metoprolol, sotalol, atenolol, amiodarone, sotalol, bretylium, verapamil, and diltiazem. 